Nitrogen dynamics model for a pilot field-scale novel dewatered alum sludge cake-based constructed wetland system

• Published in: Environmental technology Vol. 36; no. 6; pp. 732 - 741
• Main Authors: Kumar, J.L.G, Zhao, Y.Q, Hu, Y.S, Babatunde, A.O, Zhao, X.H
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 19-03-2015; Taylor & Francis Ltd
• Subjects: adsorption; Algae; alum; alum-sludge; ammonia; ammonification; ammonium nitrogen; bacteria; computer software; constructed wetlands; denitrification; dissolved oxygen; environmental technology; farmed animal species; Models, Theoretical; nitrate nitrogen; Nitrates; nitrification; Nitrogen; Nitrogen - isolation & purification; Nitrogen Compounds; simulation models; Sludge; solar radiation; STELLA; system dynamics; temperature; volatilization; wastewater; Water Purification; Water treatment; Wetlands; British Isles; alum-sludge; system dynamics; adsorption; nitrogen; STELLA
• ISSN: 1479-487X; 0959-3330; 1479-487X
• DOI: 10.1080/09593330.2014.960476

A model simulating the effluent nitrogen (N) concentration of treated animal farm wastewater in a pilot on-site constructed wetland (CW) system, using dewatered alum sludge cake (DASC) as wetland substrate, is presented. The N-model was developed based on the Structural Thinking Experiential Learning Laboratory with Animation software and is considering organic nitrogen, ammonia nitrogen (NH ₃) and nitrate nitrogen (NO ₃-N) as the major forms of nitrogen involved in the transformation chains. Ammonification (AMM), ammonia volatilization, nitrification (NIT), denitrification, plant uptake, plant decaying and uptake of inorganic nitrogen by algae and bacteria were considered in this model. pH, dissolved oxygen, temperature, precipitation, solar radiation and nitrogen concentrations were considered as forcing functions in the model. The model was calibrated by observed data with a reasonable agreement prior to its applications. The simulated effluent detritus nitrogen, NH ₄-N, NO ₃-N and TN had a considerably good agreement with the observed results. The mass balance analysis shows that NIT accounts for 65.60%, adsorption (ad) (11.90%), AMM (8.90%) followed by NH ₄-N (Plants) (5.90%) and NO ₃-N (Plants) (4.40%). The TN removal was found 52% of the total influent TN in the CW. This study suggested an improved overall performance of a DASC-based CW and efficient N removal from wastewater.